Local Area Networks are used to connect computers in such a way that they can communicate with each other at very high speeds, e.g. of the order of 10 Mbps. In larger user organizations these computers are connected to backbone networks so that different department LANs can communicate and finally the backbone network may have a bridge to a Wide Area Network (WAN) in order to communicate to the outside world. As computers become more powerful LAN's and WANs allow organizations to distribute the power and still maintain connectivity.
Many user organizations have a need to keep certain types of data secure. This may range from a small company which has a responsibility to protect its employee's confidential data, to companies working on defense related contracts, to the government security and diplomatic services. More and more of this data is being placed on computers.
Data encryption devices secure sensitive information while it is electronically transmitted, stored, or otherwise processed. Encryption systems which include both hardware devices and software programs employ a mathematical algorithm to scramble plain text, rendering it unintelligible until it is unscrambled through the use of a special digital key. The security of the system is a direct function of the possession of the key.
Many hardware-based encryptors are simple microprocessor-based systems that electronically encode data at the sending end and decode data at a receiving end. Several effective software programs run as applications programs on a user's computer system.
Hardware encryption devices provide certain advantages over application software. For example, the installation of encryption hardware has a minimal effect on the user's existing computer system. Also, an encryption process employing hardware is virtually immune to unauthorized, undetected alteration. Software, on the other hand, is susceptible to programmer modification.
There are two categories of means for providing data security on LANs connected to personal computers: the first category is comprised of software-only programs which are inexpensive but which have been found to be somewhat ineffective, and the second category of hardware/software combinations that offer adequate security but are expensive due to the addition of a circuit board.